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, srA'rE HARRY N. FARIS, OF KANSAS CITY, KANSAS, ASSIGNOR T0 KELLOGGSWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

TRUNK-CIRCUITS.

' Specification of Letters Patent.

Application filed November 26, 1915. Serial No. 63,432.

particularly'to systems in which a calling subscriber informs anopera-tor of the connection desired then disconnects, and the operatorcompletes the connection withthe desired called-for subscriber beforetrunking back to the said calling subscriber.

In systems of the above described character. which are used generally inconnection with toll work, a toll board is provided with recordingoperators positions in which terminates so-called recordin trunks, theopposite ends of which terminate at local oflices. A calling subscriberdesiring to make a.toll call first connects to a recording operatorstrunk through the medium of automatic or manual link circuit apparatus,then informs the recording operator of the toll connection desired andthereafter replaces his receix'er causing the apparatus to be restoredto normal. The recording operator, or a toll opera-tor that has reccivedinstructions from the recording operator first effects connection withthe desired called-for subscriber and then trunks back to the callingsubscriber that originated the call and informs him that the connectionwith the called subscriber may now be had. In systems of this characterit has been necessary to use two or more relays in connection with eachof the toll recording trunk circuits in order to obtain the necessarysupervision. One of the features of my invention is the provision of asimplified toll recording trunk; to the accomplishment of which'Iprovide a novel circuit arrangement for accomplishing the desired resultwithout the use of relays.

It is an object of my invention to produce an improved system that willembody desirable features of construction and cir-- cuit arrangements ina simple, eflicient and economical manner; and to the accompllsh-Patented Aug. 19, 19119.

ment of this object my invention consists in the novel details ofconstruction and circuit arrangements as hereinafter described andpointed out in the appended claims.

Referring to the accompanying drawing, I have illustrated one embodimentof my invention which. shows a so-called universal cord circuit C forconnecting a common battery subscriber A. or a local battery subscriberBto the recording operators trunk 1).. The cord circuit G-may also beused for interconnecting local battery andcommon battery lines. Thesubscribers lines A and B terminate at the central oilice in convertible line circuits L and L respectively, these circuits comprisingsimilar apparatusdiffering only in the connections. Referrmg first tothe local. battery line B, it comprises the usual cut-off relay CO, linerelay LR, and "line signal S, this circuit being so arranged that whenthe substation generator is operated the line relay LR is energized andlocked up over a local circuit, maintaining the line signal S lighteduntil an answering plug is inserted and the cut-ofi relay energized. Theline-circuit is so arranged that it may be readily converted into acommon battery line by simply changing the connections of the line andcut-off relay as shown. The common battery substation A is of awell-known type and is connected to the exchange through. the medium ofthe line circuit L which terminates in the central oflice in the linerelay LR and'cut-ofl relay CO In connection with the cutofi' relays COand CO when used for magneto service the relay G0 has its windingsconnected in series so as to provide a high resistance path for the jacksleeve to ground but when used for common battery service its windingsare connected in multiple so as to provide a lower resistance path fromthe jack sleeve. 7

This variation of resistance of the cut-off relays is for the purpose ofeffecting the operation and non-operation of the answering and callingsleeve control relays ASC and CSC.

The operators link circuit C comprises answering and calling plugs APand CP connected by the heavily marked talking conductors. Associatedwith the answering plug AP and connected to the sleeve conductor thereofis theanswering sleeve controlling relay ASC which energizes when erablyline circuit 0 crates.

. AS associated .with the answering plug connection is made with acommon battery line. so as to connect one winding of the answeringsupervisory relay AS to one side of the connected line. When connectionis made with a magneto line, the answering sleeve control relay is notoperated, thereby leaving the magneto windin of the answeringsupervisory relay AS bridged across the circuit of the calling magnetoline. As previously referred to the cut-ofi relays of the magneto andcommon battery lines are prefof a different resistance, relay CO beingsufficiently high to prevent the operation of the switching or controlrelay, relay C0 of the common battery line being of low enoughresistance to permit the operation of the switching or control relay,but in either case the cut-0E relay of the subscribers Associated withthe lug P is a calling sleeve control calling C C and a callingsupervisory relay relay CS similar to the answering sleeve control,

relay ASC and answering supervisory regs? I also provide the customaryanswerlng and calling supervisory signals AS? and CSS, respectively. Alistening key LK ispro vided for connecting the operators telephone set0 with the strands of the cord circuit and a ringing key RK is providedfor connecting the generator G to the tip and ring conductors of thecalling plug CP.

The recording trunk D terminates at the localex'change in multiple jacksJ which appear before the different local operators;

operated in its opposite end terminates in a two-way listening key uponthe recording position of the toll board.- If the listening key LK isone direction, the operators set 0 is connected to the trunk circuit andif operated in the opposite. direction a second operators telephone set(not, shown) may be connected to the recording trunk circuit. I

i provide a line and supervisory signal SS for denoting calls that comein over this trunk circuit. A pilot relay PR and a pilot supervisorylamp PS is provided common to the trunks that appear before therecording operators position.

Having described in general the apparatus shown upon the accompanyingdrawing, I will now describe more in detail the establishment of acircuit'connection between a calling subscriber and a recording tolloperator at the toll board. Assuming that the subscriber at the commonbattery substation A is a calling subscriber, upon the removal of thereceiver at the substation a -circuit is closed through the line relayLR over the metallic telephone line. The line relay LE upon energizing,closes a circuit through the line signal S ,'which notifies thelocaloperator that aconnection is desired.

The operator upon noting the glowing of the line lamp S inserts theanswering upon energizing,

LR thereby extinguishing the line signal S, and answering control relayASO, upon energizing, connects battery through its lower Winding to thering conductor-and a series energizing circuit is closed" The relay CO Idisconnects the line relay connects ground through the lower winding ofthe answerin su ervisory relay AS to the tip conductor,t ere yfurnishingthe'calling subscriber with the subscrib'ers metallic line circuit andtalking battery. The an-f swering supervisory relay is energized overoperates to-prevent a prematufe glowing of the answering supervisorysignal AS by opening its normal contact 2.

The operator now actuates listening key LK to connect her; telephone set0 across the strands of the cord circuit C and inquires of the callingsubscriber the'connection desired. Upon learning that a toll connectionis desired the operator restores her listening key to normal and insertsthe calling plug G into a multip)e jack J of the recording. trunkcircuit having first tested to ascertain whether the recording. trunkcircuitD is in an idle or busy condition. Upon the insertion of thecalling plug into the multiple jack J, a circuit is closed extending-from battery through the upper winding of the calling sleeve controlrelay CSC, through the sleeve contact of the calling plug GP and jack Jthe line lam SS normal contacts 3 and 4 of listenmg key LK and throughthe, pilot relay PR to ground. The Y calling control relay CSC and pilotrelay PR are energized over this circuit but the resistance of thewinding of the calling con- ,trol relay CS0 is such as not to permitsuflicient'current to flow through the line and supervisory. lamp SS tocause it to glow. The ilot relay PR, upon energizing causes the p1lotlamp PS to glow, thereby notif ing the recording operators that a callhas been extended to the recording position of the toll board. Thecalling sleeve control relay, upon energizing, connects battery throughits lower winding to the ring conductor of the cord circuit C andconnects ground through the lower winding of the calling supervisoryrelay OS to the tip conductor of tending from battery through the saidlamp,

through normal contact .6. of relay OS, alternate contact 7 of relayCSC'and through the right hand winding of the coil 8 to ground.

The connection of battery through the lower winding of the relayCSC tothe ring contact of the Jack J 2 closes a supplemental circuit throughthe lamp SS extending from battery through the lower winding of saidrelay CSC, alternate contact 9 thereof, ring conductor of the plug GPand jack J normal contacts 10 and 11 of listening key LK through lamp SSnormal contacts 3 and 4 of said keyand through the pilot relay PR toground. The line lamp SS receives sufficient current over this circuitto cause it to glow, thereby designating to the recordin operators theparticular trunk over whic the connection has been extended. The idleone of the recording operators now actuates the listening key LK toconnect her telephone set 0 across the tip and'ring conductors of therecordingcircuit D. Bridging the operators set 0 across the trunkcircuit closes a circuit through the calling supervisory rela CS, whichcircuit extends from battery rough the lower winding of the relay CSC,ring conductor of the plug GP and jack J alternate contact 10 of ey LK,retard coil 14 of the operators set 0 alternate contact 15 of key LK,tip conductor of 1 the jack J and plug GP, alternate contact 16 of CSCand through the lower winding 4 of relay CS to ground. The relay CS,upon energizing, causes the calling supervisory signal CSS tobeextinguished by opening its normal contact 6, thus notifying the localoperator at the cord circuit C that therecording operator at thetrunkcircuit D has connected to the calling line. A further result due to theoperation of the listening key LK is that lamp SS is extinguished byopening its circuit at normal contact 4 of the said key LK The recordingoperator now inquires of the calling subscriber the toll connectiondesired. After having received this information the calling subscriber Ais instructed by the operator to replace his receiver upon the switchook, the operator notifying him that she will call him back as soon asshe is able to establish connection with the desired. line, the operatorat the recording trunk D at the same time restores her listening key LKto normal. The replacement of thereceiver at the calling substation Aopens the circuit of the lower winding of the answering supervisoryrelay AS,.thereby allowing it to denergize and close a circult throughthe answering supervisory slgnal 'AS.

The circuit for the signal AS extends from battery through the saidsignal, normal contact 2 of AS, alternate contact 17 of ASCand throughthe left hand winding of-coil '8 to ground. The return of the listeningkey LK to normal opens the circuit of the calling supervisory relay CS,thereby allowing it to denergize' and return to normal, thus closing thehereinbefore traced circuit through the calling sleeve supervisory lampCSS at its normal contact 6. The local operator at the cord circuit Cnoting the glowing of the supervisory lamps AS and CSS removes theanswering plug AP and calling plug CP from jacks J and J respectively,thereby restoring the apparatus to normal.

As my invention relates only to-the apparatus used in extending aconnection from a calling subscriber to a recordingoperators position,it is thought unnecessary to further describe how the toll recordingoperator or the service operator at the toll board. completes theconnection between the called subscribers line and the originatingcalling subscribers line.

Assuming now that'the local battery sub scriber B wishes to initiate acall, the generator at the substation B is operated, thereby causing theline relay LE to energize and to lockup over a local circuit extendingfrom ground through alternate contact 18 of LB, said relay LR, normalcontact 19 of relay CO, alternate. contact 20 of relay LR to battery.Relay LR, upon energizing, also closes a circuit through the line signalS. The operator upon noting the glowing of the line signal S inserts theanswering plug AP of cord circuit G into the jack J of the callingsubscribers line thus closing a circuit extending from ground throughthe windings of the cut-oft relay CO in series, sleeve contact of thejack J and plug AP and through the upper winding of relay AS to battery.As before mentioned the resistance of the two windings of the cut-ofi'relay CO in series is such as not to permit suficient current to flow tooperatively energize relay ASC. Howcircuit C and inquires of the'callingsubscriber the connection desired. The connection from hereon is thesame as hereinbefore described up to the point where the magnetosubscriber signals for disconnection. The magneto subs iber, havinginformed the recording operator the connec-' tion desired operates thegenerator at the substation B, thereby causing the answering supervisoryrelay AS to. ener ize causing it to close a locking circuit for itselfin series with answering supervisory signal AS, extending said lamp AS,alternate contact 2 of vAS, normal contact 21 of listening keyLK, normalcontact 22 of ASC and through the lower winding ofsaid relay AS toground. The glowing of the answering supervisory lamp AS is continuousand notifies the operator at the cord circuit C that the subscriberatthe substation B desires disconw nection. The operator at cord circuitC now removes plugs AP and GP from ]acks J and J 2 respectively andoperates the listenin key LK to open its normal contact 21 a suicientlength of time to permit the answering supervisory relay AS todeenergize thereby extinguishing the supervisory signal AS.

As the apparatus associated with the'calling end of the cord circuit issubstantially the same in its operationv as that associated with theanswering end of the cord circuit, it is thought unnecessary to go intodetail to explain the manner in which the cord circuit C may be used toestablish connec tion between common battery lines, local battery lines,a common battery and a local battery line, or between a local batteryand a common battery line.

From the foregoing it will be seen that I have provided a system inwhich the local operator connects direct to a' recording trunk, whichrecording trunk is not provided with individual relays as has heretoforebeen used.

Although I have shown only one link circuit used in connecting thecalling subscriber with the toll recording trunk, it is obvious that anynumber of link or trunk circuits ma be used for extending a call from acalling subscriber to a recording operator. It is to be understood thatI do not wish to limit my invention to the specific circuits illustratedas it is evident that it is applicable to a variety of systems and it isto be understood that I' contemplate employing my invention in otherways than' that shown, as for example, the jacks J 2 may terminate inthe banks of automatic apparatus in which case automatic apparatus wouldbe used for extending a call from a calling subscriber to the recordingoperators trunk. Therefore, I do not desire to be limited to the exactstructure as shown and described but I aim to cover broadly all suchchanges and 'modifications as come within the spirit and scope of theappended claims.

Having described my invention, what I claim as new and desire to secureby United States Letters Patent, is:

1. In a telephone system, a link circuit provided with terminalcontacts, atrunk circuit also provided with terminal contacts,

a signal device associated with said trunk circuit, means for connectingthe said link from battery through the circuit to the said trunk circuitthrough the medium of their terminal contacts, a circuit for the saidsignal device including terminal contacts of said trunk and linkcircuits, and a supplemental operating circuit for said 'si a1 deviceincluding othersof said termlnal contacts.

2..In a telephone system, the combination with a plug ended link circuitconnected to a jack ended trunk circuit, a signal device for saidtrunk'circuit, a circuit for said signaling device includin a contact ofsaid jack and said plug, an means controlled over said circuit forclosing a supplemental'circuit for said signalin device iricluding asecond contact of said' ack and P i 3. In a telephone system, a linkcircuit provided with a three-conductor terminal, a trunk circuitprovided with a three-conductor terminal, asignal associated 'with saidtrunk circuit, means for connecting the terminal ofsaid link circuit tothe terminal of said trunk circuit thereby closing a circuit for saidsignal including a contact of each of said terminals, and means responasupplemental circuit for said signal including other contacts of saidterminals.

4. In a telephone system, a manual link circuit, a trunk circuitextending to an operators board a visual signal and a manually operatedswitching device for said trunk circuit, means for connecting said linkscircuit to said trunk circuit thereby closing a circuit through saidvisual signal including a terminal contact of said link and trunk cir-,sive to the closure oi said circuit to close cuits, means associatedwith said link circuit responsive to said connection for closing asupplemental operating circuit for said vis-' ual signal including otherterminal contacts of said link and trunk circuits, and means foroperating said switching device to efiace .said visual signal.

5. In a telephone system, a calling subscribers line, a link circuit forconnection thereto, a trunk circuit extending to an. operators boardprovided with a visual signal, saiditrunk circuit including only contactsprings and connecting conductors, means for connecting said linkcircuit to said trunk circuit thereby closing an operating circuit forsaid visual signal including a conductor of said link'and trunkcircuits, manually controlled switching means located at said operatorsboard for connecting an.

operatons telephone to said trunk circuit and means responsive to theoperation 0 said switching means for eflacing said visual signal.

6. In a telephone system, a calling subscribers line, a link circuit forconnection thereto, a trunk circuit terminating at an operators boardprovided with a visual signal, s aid trunk circuit including onlycontact springs and connecting conductors, means for connecting saidllIlk circuit; to

said trunk circuit thereby closing a circuit for, said visual signal;and means for: subsequently openin the circuit oi said; visual signal bymanua y operating said? contact springs.

7. In a telephone system, a; calling; subscribcrs line circuit, a linkcircuit connected thereto, a trunk circuit extending; to: an operators.board, said, trunk circuit providedi onlyiwith a visual contact.springs. and connecting conductors, means for connecting said link,circuitto said trunk circuit therebyv operating saidi visual over aconductorof said trunk and link circuits, and manually controllablelocated at. said, operators. board for operating said contact springs tocities said signal.

8'. In a telephone system, a link circuit provided with a multi-contactterminal, a magnet provided with a winding connected to one of saidcontacts, a. trunk circuit provided with a multi-contact terminal, asigml for said trunk circuit connected to a contactof said trunkterminal, means for vconnecting said link terminal to said trunkterminal thereby including said magnet winding and said signal in seriescircuit, and means responsive to the energlzation of said magnet forclosing a supplemental circuit for said signal through another contactof said link and trunk terminals.

9. A telephone system including a plugended link circuit, a jack-endedtrunk circuit rovided with only contact springs, a

, visua signal and connecting means, manual means for connecting saidplug to said jack thereby closing an operating circuit for said signalincluding a conductor, a contact of said link plug and trunk jack, andmanual means for operating said contact springs to eflt'ace said visualsignal.

10. A telephone system including a plugended link circuit provided witha signal, a jack-ended trunk circuit provided with only contact springs,a visual signal and connecting conductors, arelay for said link circuitfor controlling said signal, a circuit for said link circuit relay; andfor said trunk signal including contacts of said plug and jack, andmeans controlled by the energizatibn of said relay for closing, asupplemental circuit for said signal.

A telephone system.- including a link circuit provided with aconnection. terminal, a trunk circuit appearing in a plurality of trunk.operators positions and also pros vided with a connection terminal, asignal individual to said trunk circuit, a. circuit for said signalincluding a contact of the terminals of said. link circuit and saidtrunk circuit, and means located each of said trunk. operators positionsfor eiiacing said signal.

12. A telephone system including an A- operators link circuit, aB-operators trunk circuit. appearing in a plurality of trunk operators?positions, manual means for connecting said link circuit to said trunkcircuit, a signal individual to said trunk circuit, and means-located atany one of said tions, and means located at each of said trunk operatorspositions for connecting the associated trunk operators tele hone withsaid trunk circuit and for e acing said signal. a

Signed by me at Kansas City, county of Wyandotte and State of Kansas inthe presence of two witnesses.

HARRY N. FARIS.

Witnesses:

W. F. THROCKMORTON, E. Benson.

